I disagree about the CPL(H) exam questions being easier; as far as I could tell from the Question banks, the CPL questions are the same as ATPL. The difference between CPL and ATPL is that the syllabus is not so broad and there are fewer questions per paper, therefore, if starting out on ground school, CPL could well be seen to be easier.
However, if you've covered the syllabus, satisfactorily completed the progress tests with your school, the sit the ATPL exams anyway.
The ATPL(H) and CPL(H) Principles of Flight IS exactly the same paper.
Cheers
Whirls